The specific aims of this Award are 1) to identify the prevalence and patterns of alcohol and other drug use during the first 2 years after the birth of a child among a sample of adolescent mothers; 2) to identify predictors of alcohol and other drug use at 12, 18 and 24 months postpartum; 3) to examine the relationship between alcohol and other drug use and high-risk sexual behaviors (unreliable contraception and STD prevention practices) within a sample of adolescent mothers; 4) among adolescent mothers who experience a subsequent pregnancy within the first 2 years following the birth of a child, a) to examine the relationship between alcohol and other drug use and adequacy of prenatal care received and b) to identify the prevalence, patterns, and predictors of alcohol or drug use during pregnancy; and 5) to examine differences in findings from Aims 1 through 4 among Black, White, and Mexican-American adolescent mothers. A prospective, cohort design will be used in this study. Approximately 900 adolescent mothers will be enrolled, including 300 each of Black, White and Mexican-American adolescents. Subjects will be recruited from the Adolescent Postpartum Unit at the University of Texas Medical Branch, Galveston during the immediate postpartum period. Three-, 6-, 12-, 18-, and 24-month follow-up surveys will be mailed to all participants, with an aggressive attrition reduction strategy, including postcard and telephone calls to track subjects, and monetary compensation for their participation on this project. Lifetime, 3-month, 30-day and during pregnancy use of alcohol and other drugs will be measured at each assessment period. Subjects who are pregnant at the 24-month assessment will be sent a 30- and 36-month survey, as needed, to insult that complete information on drug use during pregnancy and adequacy of prenatal care is collected on all patients who experience a subsequent pregnancy.